Methods of making medical devices

Abstract

Scaffold-supported metal or pseudometallic film covers suitable for use as medical devices are disclosed together with methods of fabricating the devices. Methods for making the medical devices consist of either providing or forming a scaffold, then depositing a metallic or pseudometallic film cover onto the scaffold in such a manner as to form an integral, substantially monolithic junction between the deposited cover material and the scaffold.

1. A method of making a medical device having a covered scaffold, comprising the steps of:
 a) Forming a plurality of structural scaffold members with an interstitial area between the plurality of structural scaffold members in association with a deposition substrate; 
 b) Depositing a cover-forming material onto the formed scaffold, thereby monolithically joining the scaffold and the cover-forming material; disposing a second scaffold member onto the cover-forming material; depositing a sacrificial material onto the second scaffold member and the cover-forming material; removing portions of the sacrificial material to expose portions of the second scaffold member; depositing a second cover-forming material onto the exposed portions of the second scaffold member and the sacrificial material; 
 c) Creating a plurality of openings passing through the cover-forming material and over the interstitial area; creating a plurality of openings in the second cover-forming material that do not overlie the second scaffold member; 
 and 
 d) Releasing the monolithically joined scaffold and cover-forming material from the deposition substrate; removing the sacrificial material to form a void plenum between the cover-forming material and the second-cover forming material; and loading at least one pharmacologically agent into the void plenum between the cover-forming material and the second cover-forming material. 
 
     
     
       2. The method of  claim 1 , wherein step a) further comprises the steps of:
 i) Forming a pattern associated with the deposition substrate corresponding to a geometry for the scaffold; 
 ii) Depositing a scaffold-forming material onto the patterned substrate; 
 iii) Removing regions of the deposited scaffold-forming material. 
 
     
     
       3. The method of  claim 1 , wherein step a) further comprises the steps of:
 i) Forming a pattern of recesses in the deposition substrate corresponding to a geometry for the scaffold; and 
 ii) Engaging a scaffold into the pattern of recesses in the deposition substrate. 
 
     
     
       4. The method of  claim 3 , wherein step i) further comprises a step of gravure calendaring the pattern. 
     
     
       5. The method of  claim 3 , wherein step i) further comprises a step of embossing the pattern of recesses in the deposition substrate. 
     
     
       6. The method of  claim 3 , wherein step i) further comprises a step of etching the pattern of recesses in the deposition substrate. 
     
     
       7. The method of  claim 1 , wherein step a) further comprises a step of disposing a scaffold onto the deposition substrate. 
     
     
       8. The method of  claim 2 , further comprising after step iii) the steps of:
 (1) depositing a sacrificial material onto the scaffold-forming material and the deposition substrate; and 
 (2) planarizing the sacrificial material to expose the scaffold; and removing the sacrificial material to create an open region between the structural scaffold member and the cover material to serve as a slip plane for expansion and relative movement of the scaffold member and cover material. 
 
     
     
       9. The method of  claim 8 , wherein step c) further comprises the step of forming the plurality of openings in the cover material in regions where the cover material overlays the sacrificial material. 
     
     
       10. The method of  claim 8 , wherein step (2) further comprises the step of planarizing the sacrificial material to expose only at least one terminal end portion of the scaffold such that the at least terminal end portion of the scaffold member are exposed to integrally joins the at least terminal end portion with the cover material and intermediate portions of the scaffold material. 
     
     
       11. The method of  claim 2 , wherein steps b) and ii) each further comprise the step of vacuum depositing the cover-forming material and scaffold-forming material, respectively. 
     
     
       12. The method of  claim 2 , wherein b) further comprises the step of electrochemically depositing the cover-forming material. 
     
     
       13. The method of  claim 1 , wherein the cover forming material is a shape memory alloy having an austenite phase transition temperature is greater than 37° C. 
     
     
       14. The method of  claim 1 , wherein in step b the cover forming material is sputter deposited onto the scaffold and substrate. 
     
     
       15. The method of  claim 1 , wherein the pharmaceutically active agent is loaded into the medical device, with a suitable carrier, excipient or matrix. 
     
     
       16. A method of making a medical device having a structural scaffold and a cover, comprising the steps of:
 a) Providing a substrate suitable for vacuum deposition of biocompatible metals and pseudometals thereupon, the substrate having a pattern imparted thereto corresponding to the structural scaffold including an interstitial area between the adjacent structural scaffolds; 
 b) Vacuum depositing a scaffold-forming biocompatible metal or pseudometal onto the substrate and into the pattern; 
 c) Planarizing the scaffold-forming biocompatible metal or pseudometal to a surface of the substrate such that at least a portion of the scaffold-forming biocompatible metal or pseudometal in the pattern is substantially co-planar with the surface of the substrate; 
 d) Vacuum depositing a cover-forming biocompatible metal or pseudometal onto the substrate and the scaffold-forming biocompatible metal or pseudometal, vacuum depositing a second scaffold forming material on the cover-forming biocompatible metal or pseudometal, vacuum depositing a sacrificial material on the second scaffold forming material, and vacuum depositing a second cover-forming biocompatible metal or pseudometal on the second scaffold forming material, and removing the sacrificial material to form a void plenum between; 
 e) Forming a plurality of openings in the deposited second cover-forming biocompatible metal or pseudometal which do not overlay the second structural scaffolds and loading at least one pharmacologically agent into the void plenum between the cover-forming material and the second cover-forming material; and 
 f) Removing the substrate from the deposited scaffold-forming and cover-forming biocompatible metals or pseudometals. 
 
     
     
       17. The method of  claim 16 , wherein step c) further comprises the step of vacuum depositing a sacrificial material onto the scaffold-forming biocompatible metal or pseudometal and substrate. 
     
     
       18. The method of  claim 17 , after step c), further comprising the step of planarizing portions of the sacrificial material to expose only terminal end portions of the scaffold-forming biocompatible metal or pseudometal. 
     
     
       19. The method of  claim 18 , wherein step f) further comprises the step of removing the sacrificial material.